Signal generation

ABSTRACT

In order to automatically add measured amounts of a catalyst or other substance to a chemical reaction as needed, a signal representing a specific reaction condition is utilized to generate a pulse which has a width representative of the magnitude of said signal. An integrator then adds the pulses and after a predetermined total pulse time triggers an actuating mechanism which performs the operations necessary to add a substance to the chemical reaction.

United States Patent Thornhill et al.

[ Mar. 14, 1972 [221 Filed:

[54] SIGNAL GENERATION [72] Inventors: William J. Thornhill; Richard O.Welty,

. both of c/o Phillips Petroleum Co., Bartlesville, Okla. 74003 Apr. 30,1969 [21] Appl.No.: 820,585

[52] US. Cl ..307/l06 [51] Int. Cl. [58] Field ofSeareh ..307/106;137/455, 505,505.13;

[56] References Cited UNITED STATES PATENTS 3,181,014 4/1965 Clark..307/l06 X Primary Examiner-Hennan J. Hohauser Attorney-Young and Quigg[5 7] ABSTRACT In order to automatically add measured amounts of acatalyst or other substance to a chemical reaction as needed, a signalrepresenting a specific reaction condition is utilized to generate apulse which has a width representative of the magnitude of said signal.An integrator then adds the pulses and after a predetermined total pulsetime triggers an actuating mechanism which performs the operationsnecessary to add a substance to the chemical reaction.

9Clalms, llDrawingFlgures PATENTEDHAR14 I972 3, 649,842

SHEET 1 OF 4 SIGNAL PULSE GENERATOR INTEGRATOR ACTUATING MECHANISMINTEGRATOR ACCUM.

AIR 4o 42 37 15 1 l6 AIR OUT IN Fi'G. 2

INVENTORS w J. THORNHILL BY R.O.WELTY ATTORNEYS PAIENIEDII/IR 14 I972PRESSURE PSIG sum 2 OF 4 I4 PSIG IN PIPE 44 7 PSIG IN PIPE PRESSURESWITCH 3O ACTUATION PRESSURE I 6 PSIG 5 PSIG IN PIPE O I l I I l I l I l0 I 2 3 4 5 6 7 e 9 IO TIME SECONDS I]\VEN'I'OR5 F/G. 4 w. J.THOF'2NHIII B) R.O.WEI TY A 7' TORNE V5 PATENTEUMAR 14 I972 SHEET 3 [IF 4 LATCHING2 RELAY 8O 84 FIG. 5A

INVEN'I'ORS J. W. THORNHILL BY R0 WELTY PATENTEDMARMIQR 3,549,

sum u UF 4 3 INVENTORS J. W. THORNHILL BY R.O. WELTY ATTOPNfYS SIGNALGENERATION In U.S. Pat. No. 3,167,398, the disclosure of which isincorporated herein by reference, there is disclosed metering apparatuscomprising a rotatable member having a chamber extending therethrough,and means to alternately accumulate and discharge through said chamberas the member is rotated measured amounts of material thereby insuringaccurate and controlled feed rate of that material, e.g., catalyst, to areceiver, e.g., a polymerization reactor. The operation of such meteringdevices requires the rotatable member to be rotated through a finite arcto align the chamber therein with the inlet and exit apertures of thedevice, pause a finite length of time to allow substantially completedischarge of the material in the chamber through the exit aperture andcharging of a second chamber to be subsequently discharged, and thenrotated through another finite arc to move and hold the chamber fromcommunication with the exit aperture until another measured amount ofmaterial is desired to be discharged. Generally, the cycle rate of suchmetering devices is presently manually set by an operator and remains atthe set cycle rate until reset by an operator regardless of changes inthe process which the device is feeding. These changes generally requirea change in the feed rate, i.e., cycle rate of the device, thereto.Thus, it is extremely important to have an operation wherein the cyclerate of the metering device is responsive to at least one processvariable and/or at least one property of the product.

However, it was found that conventional cyclic actuators could noteffect a sufficiently lengthy pause between the two arcs of rotation inthe cycle of the metering device and therefore did not allow sufficienttime for the chamber of the metering device to completely discharge thedesired quantity of material. Attempts to adjust these conventionalactuators only resulted in jerky, erratic motion causing considerableleakage of the metering device as well as increased wear and generallypoor performance of that device.

Broadly, a method of this invention involves producing a signal ofvariable time interval-constant duration pulses which signal is inproportion to a signal representative of a measured process variableand/or a property of the product. This method includes first producing asignal of variable duration-constant time interval pulses which signalis proportional to the signal representative of the process and/orproperty and then converting that signal to the desired signal ofvariable time interval-constant duration pulses.

By variable duration-constant time interval pulses, it is meant asignal, be it electrical, hydraulic, pneumatic, and the like, which isbroken up into substantially constant time intervals and during eachtime interval there is produced a pulse, e.g., a flow of electrons,etc., which will last for a variable time duration depending upon themagnitude of the signal representative of the process variable and/orproperty measured, but the maximum of which duration is equal to or lessthan the time interval in which that pulse is produced. For example, ifthe time interval is 10 seconds, a pulse produced during that timeinterval can vary from to or slightly less than 10 seconds and if thesignal representative of the process variable and/or property increasesin magnitude, e.g., in the case of pneumatic signal increases inpressure, the time duration of each pulse in each time interval willincrease toward the 10- second maximum until the first signal remainsconstant or decreases in magnitude in which case the time duration ofeach pulse in each time interval will become constant or decrease inlength, respectively. By variable time interval constant durationpulses, it is meant asignal wherein each pulse produced lasts for thesame time duration but that each substantially constant time durationpulse is separated from the other by a variable time interval so that asthe time duration of each pulse in the variable time duration-constanttime interval signal increases in response to increased magnitude of thesignal representative of the process variable and/or property, the timeinterval between the constant duration pulses in the variable timeinterval-constant duration pulse signal becomes less and therefore is inproportion to the magnitude of the first signal representative of theprocess variable and/or property. Generally, the first signal as withthe other signals mentioned above can be electrical, pneumatic,hydraulic and the like, and is composed of a pulse having an indefiniteand variable time duration and having a varying magnitude during thattime duration.

Further according to this invention a variable duration pulse generatoris provided which during substantially equal successive time intervalsproduces a source of fluid under pressure and passes said fluid past apressure switch and out of the system. Depending upon the pressure ofthe fluid passing through the pressure switch, that switch may not closeat all or may be closed for any length of time up to the length of thetime interval during which the fluid is passed through the pressureswitch. The variable duration pulse, i.e., the time in each intervalduring which the pressure switch is closed, is accomplished by varyingthe rate of flow of the pressurized fluid through the pressure switch inresponse to the magnitude of the signal responsive to the measuredprocess variable and/or property of the product. This apparatus canfunction electrically, pneumatically, hydraulically, etc.

In the drawing,

FIG. I shows schematically a system utilizing the pulse generatingapparatus of this invention.

FIG. 2 shows a variable duration pulse generator of this invention.

FIG. 3 shows graphically operational characteristics of the apparatus ofFIG. 2.

FIG. 4 shows integrator apparatus suitable for use in the system of FIG.1.

FIG. 5 shows a metering device actuating mechanism.

FIG. 5A shows an alternative time delay means which can be used in themetering device actuating mechanism of FIG. 5.

FIG. 5B is a schematic electrical representation of solenoid actuatedrelay switch 98 which is shown in FIGS. 5 and 5A.

FIG. 6 shows relative relationships of the cams of the apparatus of FIG.5 during one cycle of operation.

FIG. 7 shows a metering device actuating mechanism.

FIG. 7A shows an alternative time delay means which can be used with themetering device actuating mechanism of FIG. 7.

FIG. 8 shows the relationships of the cam of the apparatus of FIG. 7through one cycle of operation.

FIG. 1 shows a variable duration pulse generator 1 connected to anintegrator 2 which in turn is connected to metering device actuatingmechanism 3. Actuating mechanism 3 is connected through shaft 4 tometering device 5. Signal 6 is the first signal or signal representativeof a measured process variable and/or property of the product. Ifdesired, first signal 6 can be an arbitrarily selected, manuallyproduced signal. As an example, signal 6 can be the output signal of aconventional temperature recorder controller which is operativelyconnected in a conventional manner through a differential thermocoupledevice to the interior of a pipe carrying therethrough cooling water onits way to the cooling jacket of a polymerization reactor. If signal 6is pneumatic, it is preferably in the range of 3 to 15 p.s.i.g. Thesensed differential temperature of the cooling water entering andleaving the jacket will determine the magnitude of the output signal ofthe temperature recorder controller and it is this signal and themagnitude thereof which determines the duration of the pulse in eachtime interval of the intermediate signal 7 put out by variable durationpulse generator 1. If the output signal of the temperature recordercontroller is, for example, pneumatic an increase in the pressure ofthis signal, representing an increase of temperature of the monomer inthe pipe, is impressed on the variable duration pulse generator and theeffects thereof are shown in detail in the discussion of FIG. 2, infra.Signal 7 from generator 1 is then passed to integrator 2 which convertssignal 7 to signal 8 which signal is composed of a series of pulses eachof substantially the same time duration and each separated from theother by variable time intervals. Signal 8 is then used to activateactuating mechanism 3 which converts signal 8 to a rotary mechanicalmotion manifested in the rotation of shaft 4 which in turn operatesmetering device in the cyclical manner required by that device. Meteringdevice 5 can be that apparatus disclosed in US. Pat. No. 3,167,398, andsimilar known types of apparatus.

Thus, due to the measured change of a process variable which is passedto generator 1 in the form of signal 6 the variable duration pulse putout by generator 1 in the form of signal 7 is changed accordingly andthe variable time interval put out by integrator 2 is also changedaccordingly so that the actuating mechanism 3 which operates in responseto signal 8 is also accordingly efiected and in turn operates meteringdevice 5 in relation to the effect thereon by signal 8 thereby causingthe cyclical operation of metering device 5 to be responsive to thechange in the process variable manifested in signal 6. If thetemperature of the monomer increases above normal the pressure of thepneumatic signal 6 increases which increases the duration of each pulsein each time interval of signal 7 which shortens the time intervalbetween constant duration pulses of signal 8 which actuates mechanism 3faster than is normal with the result that metering device 5 is operatedfaster than normal.

In FIG. 2 there is shown a variable duration pulse generator wherein acam switch 10 is driven by a motor 11 so that for a given interval oftime the cam switch is open a part of the interval and closed anotherpart of that interval, and this sequence is repeated continually therebyproducing a continuous series of substantially constant time intervals.Switch 10 and motor 11 are electrically connected by electrical lines 12and 13 so that motor I] constantly drives cam switch 10 and when camswitch 10 is contacting element 14 an electrical circult is closedbetween normally open solenoid valve 15 and normally closed solenoidvalve 16 by means of electrical lines 17, 18, and 19. Between valves 15and 16 is air accumulator 20 which is in open communication with valves15 and 16 through pipes 21 and 22, respectively. Accumulator 20 isopenly connected to a source of air through conduit 22, valve 16 andconduit 23. The amount of air passed into accumulator and therefore themaximum pressure of the air in accumulator 20 produced while normallyclosed valve 16 is open is controlled by needle valve 24.

Normally open pressure switch 30 is electrically connected to integrator2 through electrical lines 31, 32, and 33. Integrator 2 is alsoconnected to conduit 19 by electrical line 34. Pressure switch 30 isopenly connected through pipes 35, 36, and 37 to valve 15 andaccumulator 20. Throttle valve 38 is openly connected between pipes 36and 37 and adapted to vary the rate of flow of air from accumulator 20into pipe 36.

Pipe 36 is also in open communication with motor valve 39 through pipe40 and bleed valve 41 through pipe 42. Air from accumulator 20 passesout of the system via pipe 43. The rate at which air passes out of thesystem through 43 can be varied by varying the opening of throttle valve39 in response to the magnitude of the pressure ofa pneumatic air signalpassing to motor valve 39 through pipe 44. The air signal in conduit 44is the signal that is representative of the measured process variableand/or property of the product.

In operation and by way of example, cam switch 10 and timing motor 11are adjusted to produce a time interval of 10 seconds. That is, thesubstantially constant time intervals in the signal passed to integrator2 through line 33 is 10 seconds. During the first portion of the 10second interval, about 2 seconds, the cam switch is actuated bycontacting member 14 thereby closing normally open valve 15 and openingnormally closed valve 16 so that air is passed into accumulator 20 andis allowed to accumulate to a predetermined maximum pressure, in thisexample p.s.i.g. After passage of this first portion of the timeinterval cam switch 10 is deactivated by moving from contact with member14 and normally open valve 15 is opened and normally closed valve 16 isclosed thereby allowing the pressurized air in accumulator 20 to passthrough pipes 21, 37, 36, 40, and 43 out of the system and also intopipe 35 where sufficient pressure will activate pressure switch 30.Bleed valve 41 is adjusted so that when motor valve 39 is substantiallycompletely closed, the pressurized air in accumulator 20 will be loweredto the actuation pressure of pressure switch 30 before the next 10second interval starts and accumulator 20 is repressurized with new air.Throttle valve 38 can be adjusted so that when motor valve 39 is wideopen the pressure in pipe 35 does not reach a pressure sufficient toactuate pressure switch 30, in this example 6 p.s.i.g, or is justsufficiently high to actuate pressure switch 30 for only a small amountof time, for example about 3 seconds.

Thus, when signal 44 varies in magnitude, for example increases inpressure, the opening in motor valve 39 is pinched down to therebyrestrict the flow of air therethrough from pipe 40 thereby increasingthe pressure in pipe 35 and forcing pressure switch 30 closed for alonger period of time than is normal. When this is effected, a variableduration pulse, in this case of increased duration, is passed throughline 33 to integrator 2 during each 10 second time interval. Therefore,a variable duration-constant time interval signal is passed tointegrator 2, the variable duration pulse of that signal beingresponsive to the signal in pipe 44 which in turn is responsive to themeasured process variable or property of the product. Generally, thepneumatic signal in pipe 44 will vary from a 3 to 15 p.s.i.g. magnitude.

lf pressure switch 30 is adjusted so that under normal conditions it isclosed for a finite period of time, the pulse generator of thisinvention can send pulses of longer duration to the integrator inresponse to increased pressure of the signal in pipe 44 thereby speedingthe operation of integrator 2 or can keep pressure switch 30 open longerthan normal thereby sending pulses of shorter duration than normal tointegrator 2 thereby slowing the operation of that integrator inresponse to lower pressures than normal in pipe 44.

FIG. 3 shows a graph wherein time is plotted against pressure onpressure switch 30 so that when accumulator 20 is charged up to a 25p.s.i.g. maximum and then allowed to pass its pressurized air out of thesystem under normal conditions, arbitrarily set as normal at a 7p.s.i.g. signal in pipe 44, pressure switch 30 will remain closed for 4seconds. However, if the signal in pipe 44 increases to a magnitude of14 p.s.i.g. in response, for example, to a temperature increase of themonomer above-mentioned, motor valve 39 will be pinched down so that thepressurized air is not removed from the system until the end of thel0-second time interval and therefore pressure switch 30 stays closedfor substantially the whole time interval of 10 seconds. Similarly, ifthe signal in pipe 44 should fall below the normal 7 p.s.i.g. to 5p.s.i.g., motor valve 39 will open further thereby allowing thepressurized air in accumulator 20 pass out of the system more rapidlyand pressure switch 30 is thereby closed for only 3 seconds. Thus, itcan be seen that depending upon the magnitude of the signal in pipe 44the relation of the pulse sent to integrator 2 during each equal timeinterval will vary in direct proportion and pulse generator 1 istherefore supplying to integrator 2 a variable duration-constant timeinterval signal.

Although any type of conventional apparatus which can receive and storesignals of variable duration until a predetermined amount of thesesignals has been received and then produce a signal of constant durationpulses can be employed as an integrator of this invention, an example ofsuch apparatus is shown in FIG. 4. ln integrator 2 of FIG. 4, there is atimer motor 50 which rotates a shaft 51 which in turn carries androtates two cam means 52 and 53 each with a similar indentation 54 and55 in the periphery thereof. Cam followers 56 and 57 are connected toelectrical switches 58 and 59.

The signal is transmitted from the variable duration pulse generator 1of FIG. 2 to timer motor 50 by electrical lines 60 and 61. Switch 58 isconnected to an electrical power source (not shown) by electrical line63 and to line 60 by electrical line 64. Electrical line 65 connects theelectrical supply source to line 61. Switch 59 is connected throughelectrical line 70, electrical power supply 71 and electrical line 72,and electrical line 73 to the metering device, actuating mechanism 3(not shown).

In operation, during each second time interval pulses of varyingduration pass by lines 60 and 61 to motor thereby operating same andturning cams 52 and 53 for a time substantially the same as the durationof each pulse. When a sufficient number of pulses of sufficient durationhave operated motor 50 long enough to cause indentations 54 and 55 tocome into register with cam followers 56 and 57 switches 58 and 59 aretripped and a pulse is sent by way of lines 72 and 73 to actuatingmechanism 3. When switch 58 is tripped the electrical sources areconnected into motor 50 thereby causing same to continue to operateuntil cam follower 56 is disengaged from indentation 54 of cam 52 atwhich time switch 59 is also deactuated and the pulse to the actuatingmechanism terminated. Thus, a variable duration pulseconstant timeinterval signal from pulse generator 1 passes into integrator 2 by lines60 and 61 and a variable time interval-constant duration pulse signal ispassed from integrator 2 by lines 72 and 73 to the actuating mechanism3.

FIG. 5 shows intervalactuating mechanism of this invention wherein thevariable time interval-constant duration pulse signal from integrator 2is passed from electrical lines 72 and 73 to latching relay which isadapted by means of coil 81 to, upon receipt of a pulse from integrator2, switch contacting arm 82 from the contact on which it was left upontermination of the last received pulse (as shown in FIG. 5 contact 83)to the other contact 84 in latching relay 80. Contacts 83 and 84 areconnected by electrical conduits 85 and 86 to contacts 87 and 88 ofswitch 89. Switch 89 is connected by electrical line 90 to switch 91.Contact 92 is connected by way of electrical line 94 to switch 120 whichhas two contacting arms 121 and 122 and three contacts 123, 124, and125. Contacts 123 and 125 are connected through lines 126 and 127respectively to line 97 for control of solenoid actuated relay switch98. Details of the operation of solenoid actuated relay switch 98 areshown in FIG. 58. Contact 124 is connected to the timing motor 128 byelectrical line 129. Timing motor 128 is also connected to conduit 73 byelectrical line 130. Shaft 131 of motor 128 carries cam 132 which coactswith cam follower 133 which is adapted to move contact anns 121 and 122between two of the contact points. Switch 98 is connected by electricalline 103 to electrical drive motor 104. Electrical line 186 of motor 104and 188 of switch 98 are connected to an electrical power source. Motor104 rotates shaft 105 which shaft carries cams 106 and 107 and whichshaft is connected to the rotatable member of metering device 5. Thus,when drive motor 104 rotates shaft 105 cams 106 and 107 and therotatable member of metering device 5 are all moved together. Camfollowers 108 and 109 engage, respectively, cams 106 and 107 and areadapted to trip switches 91 and 89 back and forth from their twocontacts.

In operation, the pulse passing through contacts 84, 88 and 92 passesthrough line 94, a contacting arm 121, contact 123 and lines 126 and 97to actuate switch 98 and start operation of motor 104. After motor 104has turned cam 106 90 it moves the contacting arm of switch 91 fromcontact 92 to 93 which causes the pulse to pass through conduit 99,contact arm 122, contact 124 and line 129 to start operation of timingmotor 128. Timing motor 128 turns cam 132 until cam 132 trips switch bymoving contacting arms 121 and 122 into contact with contacts 124 and125, respectively. The time required to cause rotation of cam 132 sothat it will trip switch 120 is that amount of time required to allowthe chamber in the rotatable member of metering device to substantiallycompletely empty its contents. When switch 120 is tripped the pulseoriginally passing through contacting arm 122, contact 124 and line 129is then directed to contact 125 and lines 127 and 97 to reactivateswitch 98 and start motor 104 in operation again. After motor 104 hasturned cams 106 and 107 through another 90 arc contacting arm in switch91 is moved from contact 93 to 92 and the contacting arm in switch 89 ismoved from contact 88 to contact 87 and operation of the mechanismterminated. When the next pulse arrives it will be directed throughcontacts 83, 87, 92 and 124 thereby causing operation of timing motor128 until cam 132 reaches the point where it trips switch 120 back andthe pulse is then severed from contact 124 to contact 123 and therebyallows actuation of switch 98 and starts operation of motor 104, tostart a new cycle.

FIG. 5A shows an alternative delay means which can be used to replaceswitch 120, motor 128, cam 132, and cam follower 133 of the FIG. 5apparatus. Contact 92 of the apparatus shown in FIG. 5 is connected byway of electrical lines 95 and 97a to solenoid actuated relay switch 98.Contact 93 is connected by electrical line 100 to circuit delay device101, and lines 102 and 97a connect circuit delay device 101 to solenoidactuated relay switch 98.

In the operation of the device of FIG. 5 using this alternative circuitdelay device, a pulse received from integrator 2 causes contacting arm82 to switch from contact 83 to 84 and pass the pulse through contacts88 and 92 through lines 95 and 97a to switch 98 thereby causing it toclose and start motor 104 in operation. After motor 104 has rotated(together with cams 106 and 107 and rotatable member in metering device5) about 90, the contacting arm of switch 91 is transferred from contact92 to contact 93 thereby causing the pulse to pass into circuit delaydevice 101 which causes the pulse to be held up and thereby interruptsthe supply of electricity to switch 98 which causes that switch toreturn to its normally open position. The circuit delay device 101 canbe any conventionally known delay device such as a Cramer Type THC-15SStyle A time delay relay made by the R. W. Cramer Company, Inc.,Centerbrook, Connecticut. After a short interval of time which issufficient in length to allow the chamber in the rotatable member ofmetering device 5 to substantially completely empty the contentsthereof, the pulse is passed by lines 102 and 97a to switch 98 whichactuates and again starts motor 104 into operation. After motor 104 hasrotated cams 106 and 107 another 90, the contacting arm in switch 91 ismoved from contact 93 back to contact 92 and at the same time contactarm in switch 89 is passed from contact 88 to contact 87. When thecontacting arm in switch 89 is passed from contact 88 to contact 87, themechanism is deactivated and will not be reactivated until a new pulseis received from integrator 2 which pulse will then cause contact arm 82of switch 80 to move from contact 84 to contact 83.

FIG. 5B is a schematic diagram of solenoid actuated relay switch 98 asit is connected in the apparatus of FIGS. 5 and 5A. When a signal isapplied to the coil of solenoid 98a through leads 190 and 97 (or 97a),contact 98b is closed thereby making a connection between line 188 andline 103. When there is no signal applied to the solenoid 98a, contact98b returns to its open position.

FIG. 6 shows the relationship of cams 106 and 107 as they have rotatedthrough the three stages of each cycle of operation of this mechanism.In Stage A double lob cam 106 and single lob cam 107 are in a positionso that no switching will occur until rotated 90 and 180, respectively.When motor 104 is operated for the first time cams 106 and 107 arerotated 90 at which time cam 106 trips switch 91 but cam 107 still has90 of rotation to follow through before it will trip switch 89. In StageC cam 106 is in position to trip switch 91 back to the position it wasin in Stage A while cam 107 has reached the first point where it is in aposition to trip switch 89 the first time. Thus, in a rotational arc of180, which is generally required by the metering device 5, cam 106 tripsswitch 91 twice while cam 107 trips switch 89 once to end the cycle.

In FIG. 7 the pulse from integrator 2 passes to switch which has twocontacts 141 and 142. Switch 140 is connected through lines 143 and 144to switch which has two contacting arms 171 and 172 connected to lines143 and 144 respectively and three contacts 173, 174, and 175. Contacts173 and 175 are connected by electrical lines 176 and 177 to electricalline 178. Line 178 is connected to solenoid 150a which, along withoperating rod 15% and valve 150e, is a part a threaded shaft 154 with apiston 155 coacting with the threaded portion and biased toward airinlet aperture 156 by I resilient means 157. Air is vented from actuator153 through vent 158. Shaft 154 is connected to shaft 159 by ratchetmeans 160. Shaft 159 carries cam 161 and is attached to the rotatablemember of metering device 5. Cam follower 162 coacts with cam 161 and isadapted to trip switch 140 back and forth from contacts 141 and 142.

In operation the pulse passing through contact 141 passes through line143, contact 173, and lines 176, 178, to operate solenoid 150a and openvalve 150a and cause rotation of cam 161 through a 90 arc. After the 90rotation cam follower 162 trips switch 140 to contact 142 therebydeenergizing solenoid 150a, closing valve 1500 and stopping rotation ofshaft 159 and passing the pulse through line 144, contact 174 and line179 to start operation of timer motor 180. After timer motor 180 rotatescam 184, cam follower 185 trips switch 170 thereby moving contacting arm172 from contact 174 to contact 175 and causing the pulse to passthrough lines 177, 178, and 149 to reopen valve 150a and cause cam 161to be rotated another 90 at which time switch 140 is retripped and thecontact arm moved back to contact 141. Here also the time required tocause cam 184 to rotate a sufficient amount to trip switch 170 is thatamount of time required to allow the chamber in the rotatable member ofmetering device to substantially completely empty its contents. Afterswitch 140 is retripped back to contact 141 any pulse that is left isemployed through line 143, contacting arm 171, contact 174, and line 179to continue operation of timer motor 180. The first portion of the nextpulse from integrator 2 is employed in like manner until cam 184 isrotated to a position where it retrips switch 170 so that contactingarms 171 and 172 are again in contact with contact 173 and 174,respectively.

FIG. 7A shows an alternative time delay device which can be used withthe apparatus of FIG. 7 in place of switch 170, motor 180, cam 184, andcam follower 185. Contact 142 of switch 140 is connected through line146 to circuit delay device 147 and then through lines 148 and 149 tosolenoid 150a of normally closed solenoid valve 150. Contact 141 isconnected to solenoid 150a through electrical lines 145 and 149. Circuitdelay device 147 can be the same type of device as disclosed in FIG. 5A.

In operation of the apparatus of FIG. 7 utilizing the alternate delaymeans of FIG. 7A, the pulse from integrator 2 initially passes throughcontact 141 and lines 145 and 149 to solenoid 1500 which opens valve1500 and causes air to be admitted to actuator 153 for a time sufficientto push piston 155 the distance required to rotate shaft 154 and 159 andratchet 160 and cam 161 90 at which time cam follower 162 trips switch140 and transfers contacting arm to contact 142, thus deenergizingsolenoid 150a, closing valve 150e, and stopping rotation of shaft 159.The pulse then passes through line 146 into circuit delay device 147 andafter the time delay sufficient to allow contents of the chamber of therotatable member of metering device 5 to be substantially completelyremoved therefrom, the pulse is passed by lines 148 and 149 to reopenvalve 150c and admit air to actuator 153 thereby causing piston 155 toadvance another distance sufficient to cause rotation of cam 161sufficiently to cause cam follower 162 to retrip switch 140 and move thecontacting arm back to contact 141 and to complete the 180 rotation ofshaft 159 after which the duration of the pulse terminates and resilientmeans 157 forces the piston back toward the inlet end 156 of actuator153 which is accomplished without disturbing the rotatable member inmetering device 5 due to ratchet 160.

FIG. 8 shows double lob cam 161 and the three stages of rotation of eachcycle of operation. In Stage A valve 150 is opened for the first timeand cam 161 is then rotated to the position of Stage B at which stagecam follower 162 trips switch from contact 141 to contact 142. Whenvalve reopens for the second time cam 16] is rotated another 90 to thatshown in Stage C at which point switch 140 is retripped from contact 142back to contact 141.

EXAMPLE A 9 p.s.i.g. signal is fed into a Honeywell pulse transmitter(Le, a variable duration pulse generator) Series 702 E 62 N having amaximum pulse rate of 540 pulses per hour, from which generator isobtained an electrical signal which is composed of a series of separate,electric pulses about 5 seconds in duration, the period of durationvarying proportionally as the pneumatic signal fed into the generatorvaries in pressure magnitude. This variable duration signal is fed intoan Indus trial Timer Corporation recycling cam switch and a Cramer TypeTEC-lSS Style A time delay relay, the two components making up theintegrator. An output electric signal is obtained from the integratorwhich is composed of a series of electrical pulses each pulse of whichis 4 seconds. The start of each pulse is separated from the start ofeach preceding pulse by a time period of 13.3 seconds which time periodvaries proportionally with the increase or decrease of duration of theelectrical pulses fed into the integrator. The output signal from theintegrator is fed into a Westinghouse solenoid piloted air operatedfour-way valve Cat. No. PD4-4l-9398 which controls the air flow to aBettis Corporation Model 301 pneumatic rotary actuating mechanism with a180 ratchet coupling which in turn is mechanically coupled to a ballcheck metering device like that of U.S. Pat. No. 3,167,398. Theactuating mechanism in response to the signal from the integratorrotates the captive ball valve of the metering device through a cycle ofrotation of the valve 90 in a given direction-pauses 2 seconds-thenrotates the valve a second 90 in the same directionthen stops.

Reasonable variations and modifications are possible within the scope ofthis disclosure without departing from the spirit and scope thereof.

What is claimed is:

1. A method for producing a resultant signal composed of a series ofpulses each having substantially equal time duration and each pulsebeing spaced from the other by a variable time interval, which resultantsignal is in proportion as to its variable time interval to a firstsignal of a varying magnitude, comprising producing in response to saidfirst signal an intermediate signal composed of a series of pulses eachhaving a variable time duration in proportion to the magnitude of saidfirst signal and each formed during one of a series of sequential timeintervals, each time interval being of substantially equal length, andthen producing in response to said intermediate signal said resultingsignal.

2. The method according to claim 1 wherein said pulses of saidintermediate signal are normally of a substantially equal time durationwhich is less than the length of one of said time intervals.

3. The method of claim 1 wherein said first signal is an electricalsignal and wherein said intermediate and resultant signals arerespective series of electrical pulses.

4. Apparatus for producing a resultant signal composed of a series ofpulses each having a substantially equal time duration and each pulsebeing spaced from the other by a variable time interval, which resultantsignal is in proportion as to its variable time interval to a firstsignal having a varying magnitude, comprising a variable duration pulsegenerator means for forming in response to said first signal anintermediate signal composed of a series of pulses each having avariable time duration in proportion to the magnitude of said firstsignal and each formed during one of a series of sequential timeintervals, each said sequential time interval being of substantiallyequal length, and an integrator means connected to said pulse generatormeans for producing in response and in proportion to said intermediatesignal said resultant signal.

5. The apparatus of claim 4 wherein said pulse generating meanscomprises means to establish a plurality of electrical pulses ofconstant duration and at a constant frequency, a gas accumulator, inletconduit means to supply gas to said accumulator, outlet conduit means toremove gas from said accumulator, adjustable flow control means in saidoutlet conduit means to adjust the rate of removal of fluid from saidaccumulator, said adjustable flow control means being adapted to beadjusted by said first signal, means responsive to said plurality ofelectrical pulses to control flows through said inlet and outlet conduitmeans so as to pressure said accumulator at said constant frequency andto open said accumulator to said outlet conduit means at said constantfrequency, and means to pass signals to said integrator means responsiveto the pressure in said outlet conduit means.

6. The apparatus of claim 5 wherein said means to pass signals to saidintegrator comprises a source of electrical energy, circuit meansconnected to said source, a switch in said circuit means, and pressureresponsive means connected to said outlet conduit means to close saidswitch whenever the pressure in said outlet conduit means exceeds apredetermined value,

7. The apparatus of claim 4 wherein said integrator means comprises amotor connected to said pulse generating means, at least one camconnected to said motor to be rotated thereby, a power source, circuitmeans connected to said power source to provide said resultant signal, aswitch in said circuit means, and means responsive to said at least onecam to close said switch when said motor has rotated a predeterminedamount and to rotate said motor an additional amount to open saidswitch.

8. Signal generating apparatus comprising means to establish a pluralityof electrical pulses of constant duration and at a constant frequency, agas accumulator, inlet conduit means to supply gas to said accumulator,outlet conduit means to remove gas from said accumulator, adjustableflow control means in said outlet conduit means to adjust the rate ofremoval of fluid from said accumulator, said adjustable flow controlmeans being adapted to be adjusted by an input signal, means responsiveto said plurality of electrical pulses to control flows through saidinlet and outlet conduit means so as to pressure said accumulator atsaid constant frequency and to open said accumulator to said outletconduit means at said constant frequency, and means to establish anoutput signal whenever the pressure in said outlet conduit means exceedsa predetermined value.

9. The apparatus of claim 8 wherein said means to establish an outputsignal comprises a source of electrical energy, circuit means connectedto said source, a switch in said circuit means, and pressure responsivemeans connected to said outlet conduit means to close said switchwhenever the pressure in said outlet conduit means exceeds apredetermined value.

1. A method for producing a resultant signal composed of a series ofpulses each having substantially equal time duration and each pulsebeing spaced from the other by a variable time interval, which resultantsignal is in proportion as to its variable time interval to a firstsignal of a varying magnitude, comprising producing in response to saidfirst signal an intermediate signal composed of a series of pulses eachhaving a variable time duration in proportion to the magnitude of saidfirst signal and each formed during one of a series of sequential timeintervals, each time interval being of substantially equal length, andthen producing in response to said intermediate signal said resultingsignal.
 2. The method according to claim 1 wherein said pulses of saidintermediate signal are normally of a substantially equal time durationwhich is less than the length of one of said time intervals.
 3. Themethod of claim 1 wherein said first signal is an electrical signal andwherein said intermediate and resultant signals are respective series ofelectrical pulses.
 4. Apparatus for producing a resultant signalcomposed of a series of pulses each having a substantially equal timeduration and each pulse being spaced from the other by a variable timeinterval, which resultant signal is in proportion as to its variabletime interval to a first signal having a varying magnitude, comprising avariable duration pulse generator means for forming in response to saidfirst signal an intermediate signal composed of a series of pulses eachhaving a variable time duration in proportion to the magnitude of saidfirst signal and each formed during one of a series of sequential timeintervals, each said sequential time interval being of substantiallyequal length, and an integrator means connected to said pulse generatormeans for producing in response and in proportion to said intermediatesignal said resultant signal.
 5. The apparatus of claim 4 wherein saidpulse generatinG means comprises means to establish a plurality ofelectrical pulses of constant duration and at a constant frequency, agas accumulator, inlet conduit means to supply gas to said accumulator,outlet conduit means to remove gas from said accumulator, adjustableflow control means in said outlet conduit means to adjust the rate ofremoval of fluid from said accumulator, said adjustable flow controlmeans being adapted to be adjusted by said first signal, meansresponsive to said plurality of electrical pulses to control flowsthrough said inlet and outlet conduit means so as to pressure saidaccumulator at said constant frequency and to open said accumulator tosaid outlet conduit means at said constant frequency, and means to passsignals to said integrator means responsive to the pressure in saidoutlet conduit means.
 6. The apparatus of claim 5 wherein said means topass signals to said integrator comprises a source of electrical energy,circuit means connected to said source, a switch in said circuit means,and pressure responsive means connected to said outlet conduit means toclose said switch whenever the pressure in said outlet conduit meansexceeds a predetermined value.
 7. The apparatus of claim 4 wherein saidintegrator means comprises a motor connected to said pulse generatingmeans, at least one cam connected to said motor to be rotated thereby, apower source, circuit means connected to said power source to providesaid resultant signal, a switch in said circuit means, and meansresponsive to said at least one cam to close said switch when said motorhas rotated a predetermined amount and to rotate said motor anadditional amount to open said switch.
 8. Signal generating apparatuscomprising means to establish a plurality of electrical pulses ofconstant duration and at a constant frequency, a gas accumulator, inletconduit means to supply gas to said accumulator, outlet conduit means toremove gas from said accumulator, adjustable flow control means in saidoutlet conduit means to adjust the rate of removal of fluid from saidaccumulator, said adjustable flow control means being adapted to beadjusted by an input signal, means responsive to said plurality ofelectrical pulses to control flows through said inlet and outlet conduitmeans so as to pressure said accumulator at said constant frequency andto open said accumulator to said outlet conduit means at said constantfrequency, and means to establish an output signal whenever the pressurein said outlet conduit means exceeds a predetermined value.
 9. Theapparatus of claim 8 wherein said means to establish an output signalcomprises a source of electrical energy, circuit means connected to saidsource, a switch in said circuit means, and pressure responsive meansconnected to said outlet conduit means to close said switch whenever thepressure in said outlet conduit means exceeds a predetermined value.